I want to update my plugins in an automated fashion. I have code to do this already, but it would require multiple http requests to check checksums of files, pull them if needed, and then update my local copy with that. This kind of automation is usually frowned upon by site owners unless they know it's going on, and have a preferred method of doing this in place. Is there a preferred API in place for doing this kind of automation?

You can access .json endpoints for most plugin pages and indexes as well as use the search.json that the site utilizes.